Several methods and approaches for fault location in high voltage power transmission systems, and power distribution systems, have been developed and employed. One approach has been to use voltage/current transducers located at terminals located at each of two ends of a section of the power line to be monitored. Inductive current transformers are used to provide a measurement of instantaneous current in a transmission line.
U.S. Pat. No. 4,559,491 entitled Method and device for locating a fault point on a three-phase transmission line, describes a one-end fault location (FL) algorithm. High accuracy of fault location using a fault locator device at one end of a line is achieved by taking into account the actual distribution of a fault current in the transmission network. This algorithm has been successfully implemented into a product in 1982 and is in operation with single and parallel transmission lines in many countries around the world. However, for certain fault conditions it is difficult to obtain accurate pre-fault quantities, such as pre-fault currents, in order to calculate an estimate for voltage drop across the fault path. Also, a disadvantage of using phase voltages and currents and zero sequence components of currents is that it is relatively difficult using these values to compensate for shunt disadvantage of using phase voltages and currents and zero sequence components of currents is that it is relatively difficult using these values to compensate for shunt capacitance effects. In addition, the fault locator method described is not suitable for single and parallel line sections which have an extra link across the ends of the sections.